The Primary Colours of Hydrogen
When Naomi Osaka walked up the white cauldron in Tokyo's National Stadium, we witnessed her lighting the first ever Olympic flame powered by Hydrogen. Olympic flames of recent vintage have used Propane and a mixture of similar gases, and if we go back far enough, even Olive Oil.
Unlike Propane, Hydrogen (H₂) produces no Carbon Dioxide when combusted and that's what makes it the hottest fuel in energy circles these days. When H₂ is burned, the only byproduct is water.
Countries around the world have given a place of prominence to Hydrogen in their Net Zero plans and Paris Agreement pathways. Indeed, it's almost unimaginable to think of creating a roadmap to reach Net Zero in 2050, without relying on Hydrogen to a significant degree.
There's increasing clarity about Hydrogen's role in the whole decarbonisation puzzle as the days go by. Once upon a time, Hydrogen was touted as the silver bullet to all polluting fuel problems. But now, its role is more nuanced and more specific.
Fuel-cells for heavy vehicles: Hydrogen is not the best solution for light vehicles. Batteries have proven to be far more efficient, and putting Hydrogen in cars is simply not an attractive proposition anymore for manufacturers. However, H₂ dominates discussions around decarbonising heavy transport, such as long-haul trucks. Fuelling time, number of fuelling stops required, space needed for the fuel system are all factors in which Hydrogen trumps batteries when it comes to long-haul trucking.
Heating: Another contested area, where Hydrogen and Electricity are going head to head is heating. Some countries are betting on H₂ to be the solution which replaces polluting natural gas, in order to provide heat to buildings. One of the main attractions of using H₂ for heating is that much of the existing infrastructure of pipes and boilers can remain the same.
Power Generation: This is probably the most wide-reaching use case, as H₂ can be used to store renewable energy (from wind or sun or any other clean source). Hydrogen fuel cells can produce electricity and can be a critical component in the grid. As a backup source, this can be particularly important.
So where does all this Hydrogen come from?
That's really where the story gets even more interesting and colours start entering the discussion (ironically enough, for a colourless, odourless gas). There are three major types of Hydrogen fuel (in addition to many more with slight changes in the production process), named after their origin in the following manner:
Brown Hydrogen: This is the more traditional, polluting method of making Hydrogen. Using water and heat, coal is taken through a process called 'gasification', and along with Hydrogen, we get Carbon Dioxide, Carbon Monoxide and Methane among others. Needless to say, this has no role in a Net Zero world.
Blue Hydrogen: This one's quite interesting as it involves new technology. Hydrogen is produced from natural gas using a process called Steam Methane Reforming, but this also produces Carbon Dioxide as a by-product. However, this Carbon is captured using Carbon Capture Utilisation and Storage (CCUS) technologies and stored away (usually underground or under the sea). This is pretty cool and cutting edge, but still does emit some Carbon.
Green Hydrogen: And finally, we come to the cleanest colour in the spectrum. Green Hydrogen is produced by electrolysis of water. A water molecule is essentially split into Hydrogen and Oxygen, and the Oxygen produced here causes no negative impact to the environment. But then, what is fuelling the electrolyser? If it's fossil-fuel supplied electricity, then we are back to square one. But if the entire process is powered by renewable energy (such as in this project by Siemens Gamesa), then we have a completely clean fuel with us.
Hydrogen is going to be pretty prominent in the years ahead and therefore, it's important to understand that there's a spectrum of Hydrogen with varying degrees of 'cleanliness'. There are several interesting battles being played out between various entities in the Blue corner and in the Green corner, and it's quite interesting to see how it's all going to turn out in the near future.
It's easy enough to say that we should go full steam ahead with only Green Hydrogen, but there are various challenges related to cost and incumbent structures that might tone down that view. The journey to Net Zero is one of transition, and incumbent energy giants see Blue Hydrogen playing an important role in the early years of that transition (while helping their business models stay robust as well). But the destination is definitely Green.
And yes, the Olympic flame was powered by Green Hydrogen.
